All the above algorithms in SafeRL-Kit are implemented under the off-policy Actor-Critic architecture. Although these model-free algorithms may inevitably encounter cost signals in the training process, they still enjoy better sample efficiency with fewer unsafe transitions compared with on-policy implementations [1]}, and can better leverage human demonstration if needed. The essential updates of backbone networks uniformly follow TD3 [2]}, and thus we can perform a fair evaluation to see which of them are best suited for safety-critical tasks.
